Researcher Studies Creek For Rangeland Effects On Water Quality

Oct 01, 2006

Elevated levels of bacteria in streams can affect water quality, the health of the aquatic ecosystem and activities such as fishing, swimming and wading, said a researcher with the Texas Agricultural Experiment Station.

Dr. John Sij, Experiment Station agronomist in Vernon, Texas, and his team are working on what might possibly be a showcase study for Texas. He and his team are measuring water quality of a rangeland watershed.

"This may be one of the first efforts on small streams such as this to get scientific involvement from the impairment through the entire process of identifying the sources of non-point pollution and looking for solutions through a watershed management plan," Sij said in an Oct. 24 statement.

As a part of the Texas Commission on Environmental Quality's Clean Rivers Program, limited testing was conducted on Buck Creek in the southeast corner of the Texas Panhandle. Tests showed bacterial levels (E. coli) in the water were sometimes elevated, indicating a potential water quality problem, Sij said.

Landowners and the Soil and Water Conservation District were concerned that possible government regulations could impact agriculture without knowing the source and scope of the contamination. The Texas Soil and Water Conservation Board and Texas Water Resources Institute were contacted. The two entities requested the Experiment Station at Vernon conduct a three-year study to determine the degree of impairment and possible solutions.

The first steps were to define the problem, Sij said. The creek is spring-fed from a rural watershed, which includes crops and grazing lands.

Buck Creek is part of the Red River Basin. Located in the subwatershed of the Lower Prairie Dog Fork of the Red River, it is an unclassified freshwater stream. According to Sij, no identifiable point sources of pollution have been determined, so any contamination would come from the watershed itself or non-point sources.

Sij said that according to EPA guidelines for contact recreation water (swimming areas), a single sample of E. coli should not exceed 394 colonies per 100 milliliter and a geometric mean of not more than 126 colonies per 100 milliliters (see Texas Surface Water Quality Standards at http://www.epa.gov/waterscience/wqs/tx).

In the Buck Creek samples collected prior to the Experiment Station's involvement, the allowable level of E. coli was exceeded in three different samples, and the fecal coliform samples exceeded allowable rates in eight different samples, Sij said.

"People swimming or wading in the creek might have been at risk," he said. "Our objective is to determine the load of the pollutant that a body of water can receive and still maintain its beneficial uses."

The load must be allocated among all potential sources of pollution within the watershed, and measures to reduce pollutant loads will need to be developed as necessary, he said.

Agriculture should not be considered the only source of pollution. Wildlife could be a significant contributor of contamination, Sij said.

"We know cattle can be a problem, but we have turkey, hogs, deer, beaver, raccoons, birds and other animals using this stream as their water source," he said.

The study established 13 monitoring sites along the creek in Donley, Collingsworth and Childress counties. In 2004, the E. coli numbers were high, exceeding water quality standards in many samples.

During the drought of 2005 to 2006 in the watershed, stream flow was greatly reduced, as were bacteria numbers, Sij said. Numerous sites were dry for months at a time.

Spring flow has been limited by vegetation and an increase in the irrigation along the creek, he said. That, coupled with several years of drought, have lessened the flow of the stream.

Some sites, however, have maintained water year-round and others are gaining water due to recent rains, Sij said. These will continue to be monitored for several more years.

Phase 1, the bacterial monitoring phase, is essentially complete, and Phase II is concentrating on bacterial-source tracking. The Phase II study will identify the animal sources contributing to the contamination, as well as their relative contribution to the total bacterial load.

The ultimate goal is to educate stakeholders and develop a Watershed Protection Plan so water quality will be able to support a healthy aquatic ecosystem and recreational activities, Sij said.

The Texas Agricultural Experiment Station is the agricultural and life sciences research agency of Texas. For more information, go to http://agresearch.tamu.edu.